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Plume CalcBeta

Exhaust plume analysis for airports and developers

Know the turbulence risk of every chiller and generator before you build.

Plume Calc computes the probability that aircraft near rooftop chillers, backup diesel generators, power-plant stacks and cooling towers meet severe turbulence or aircraft upset, run against years of hourly weather. A modern replacement for MITRE’s 2014 Exhaust Plume Analyzer.

Open the Fort Atkinson demoStart a new project

No login. Projects stay in your browser.

Illustrative side-profile risk contoursNested probability bands from yellow at 10 to the minus 7 to dark red at 10 to the minus 2, rising from a stack at the left and bending downwind to the right. Illustration only, not model output.windheight AGLdistance downwind
Probability per hour
  • 10⁻⁷
  • 10⁻⁶
  • 10⁻⁵
  • 10⁻⁴
  • 10⁻³
  • 10⁻²
Illustration, not model output.

Built for the questions consultants actually get asked

The physics follows the published MITRE approach. What changes is how you describe a real site and how quickly you get an answer.

  • Every source at its true location

    Place each chiller and generator where it actually sits. Nearby units are merged with flux-conserving rules; distant ones stay independent. Switch on the side-by-side MITRE-style averaged mode to see what averaging does to your result.

  • Operating scenarios

    “Normal ops (chillers 24/7)” versus “Emergency (chillers + generators)”. Same site, same weather, different active equipment.

  • Weather is built in

    Hourly NOAA HRRR profiles are fetched automatically through Open-Meteo: three years in a few minutes, then cached in your browser. Export the profile to MITRE’s CSV format in one click.

  • Fast enough to iterate

    Three years of hourly weather (26,280 hours) runs in seconds in your browser using Web Workers, without freezing the machine.

  • Results where you work

    Risk at a chosen altitude and a 3D “risk ceiling” on a satellite map, plus MITRE-style side-profile contour plots from 10⁻⁷ to 10⁻².

  • Real site plans

    Import a DXF. Plume Calc detects NAD83 State Plane zones in US survey feet or international feet (for example Michigan) and places the geometry for you.

  • Modern aircraft library

    Cirrus SR22, King Air, Phenom 300, G650, 737-800, A320neo and more, with cited parameters. MITRE’s four reference types and custom aircraft are included.

  • No login

    Projects live in your browser. Nothing to sign up for, nothing to install.

Why replace the 2014 tool

MITRE’s analyzer models one averaged source. For a data center with chillers and generators spread over acres, averaging can make risk vanish or distort it. Plume Calc keeps them apart.

MITRE Exhaust Plume Analyzer compared with Plume Calc
AspectMITRE Exhaust Plume AnalyzerPlume Calc
InputsOne stack, or several aligned, identical stacks. Typed into a form; Java desktop install.Any number of sources with their own position, height, diameter, velocity and temperature. Site plan import from DXF.
SourcesSingle averaged source. Equipment acres apart is collapsed into one.Each chiller and generator at its true location, with an optional averaged comparison mode.
WeatherQuery MITRE’s server (RUC/RAP, proxy settings may be needed) or load a CSV.Hourly NOAA HRRR via Open-Meteo, fetched automatically. Export to MITRE CSV, or import one.
Run timeAs little as 2 hours for 3 years with six cores, per MITRE’s guide. One customer 5-stack run took 9 min 15 s and froze the machine.3 years of hourly weather in seconds, in the browser, off the main thread.
OutputsSide-profile contour plots, 10⁻⁷ to 10⁻², saved as PNG.The same side profiles, plus risk at a chosen altitude and a 3D risk ceiling on a satellite map.
AircraftFour reference types, plus custom aircraft.Modern library with cited parameters, the same four reference types, and custom aircraft.

How it works

Four steps, in the same order as the app.

  1. 1

    Site

    Locate the project on the map or import a DXF site plan.

  2. 2

    Equipment & scenarios

    Place chillers and generators, then define normal and emergency operating scenarios.

  3. 3

    Weather

    Fetch three years of hourly HRRR profiles, or load a MITRE CSV.

  4. 4

    Aircraft → Run

    Pick aircraft and hazards, run, and read the maps and contour plots.

Where the model stands

The engine is tested against analytic similarity laws, the Briggs plume-rise law and the FAR 23 gust-loads formula. Parity with MITRE outputs on identical inputs is pending client data. The methodology page states what is verified, what is not, and what the model leaves out.

See a full run on a real site.

The Fort Atkinson demo has equipment, scenarios and weather ready to go.

Open the Fort Atkinson demoStart a new project